This invention relates to a method of forming sliding surfaces which can be suitably applied to a cylinder in an internal combustion engine, etc.
An example of a machine member having a sliding surface is the cylinder of a small air-cooled internal combustion engine. Conventionally, the sliding surface of this cylinder has been prepared by forming a hard chrome plating layer on the inner su face of the cylinder base made of an aluminum light alloy or the like, and then honing this hard chrome plating layer so that the cylinder may have a bore of predetermined dimensional tolerances. With this method, the hard chrome plating layer is generally endowed with a high hardness of Hv 800 or more, so that, in the subsequent step of honing, a very expensive honing stick, such as a diamond wheel or a borazon wheel, has to be used. Furthermore, the service life of such a honing stick is short, resulting in high production cost. Moreover, the hard chrome plating layer is rather poor in machinability, so that it is very difficult for the finish-cut dimensions and the surface roughness of the cylinder bore to be kept within the predetermined tolerances. In addition, there is a problem that, at the initial stage of use of the cylinder, the bore of the cylinder exhibits poor fitting to the sliding surface of the associated piston.